Molded patch for the air opening of molding forms



Oct. 6, 1964 M. E. KERSTEN 3,151,374

MOLDED PATCH FOR THE AIR OPENING OF' MOLDING FORMS Filed July 30, 1962 42mm/ W {Z1/0..

United States Patent yO 3,151,374 -MLDED PATCH FOR THE Am OPENING F MLDING EGRMS Merle E. Kersten, Downers Grove, lll., assigner to Ceco Steel Products @oi-poration, Chicago, lll., a corporation of Delaware Filed July 30, 1962, Ser. No. 213,439 Claims. (Cl. ZS-ZG) The present invention relates to a novel patch for use with dome-shaped molding forms employed in the production of poured concrete floors or walls of the waffle type, each domevbeing provided with an opening at the center thereof for the passage of air under sufficient pressure to dislodge and separate the form from the set concrete or molded product whereby to greatly facilitate removal of the form without deformation or damage thereto. Such method and manner of removal permits repeated reuse of these forms.

Rushing Patent No. 2,850,785, of September 9, 1958, discloses a method of and means for releasing molding forms of this general type from the molded product and involves the use of a patch of crinkled paper or pressuresensitive tape placed over the air hole at the center of the top of the domed molding form. Such, patch is intended to provide a covering for preventing the vwet concrete clogging the hole and to also provide on the underside of the paper or tape means for permitting andrdispersing the iiow of compressed air from under the crinkled or roughened undersurface of the patch and over the top of the domed surface of the molding form for the progressive separation and removal of the latter.

A patch is adhesively applied to the upper open end of the air hole of each molding form whentthe latter is placed and temporarily retained in position for concrete pouring with the patch covering and precluding Vthe wet concrete from plugging the opening. After the concrete has set upon the forms and the framework removed, the forms are successively and progressively released by the application of compressed air. ln the use of the crinkled tape or paper patch of the above mentioned patent which is located above and kadhesively affixed to the top of the form, it has been found that difficulty is frequently encountered due to the adhesive failing to adhere in cold weather, particularly when the temperature range is around freezing. Ithas also been found that at times the patches are scufied olf by workmen dragging material or equipment across the patch or by walking on it prior to actual pouring of the concrete. Also the patch of this patent must be rather accurately centered when assembled so as to properly distribute the discharged air pressure over the entire upper surface of the form.

The present invention comprehends a novel patch of molded plastic that eliminates the above objections. It can be quickly anchored in centered 'position and is positively retained in the discharge opening for the passage of air under pressure, and is so constructed and arranged as to most effectively and economically release its molding form and separate it from the surrounding poured concrete or molded product.

Another important object of the present invention is the provision of a novel plastic molded patch having a tinted `projection or longitudinally l.grooved prong of greater cross section than that of the opening into which the'projection is driven whereby to positively anchor and retain'the patch in centered operative position, vwith 'the disc or covering effectively protecting the air opening against the entrance of the wet concrete when poured.

The disc of the novel molded patch is provided with concentrically arranged ribs on its undersurface providing a plenum chamber between it and the adjoining top 3,l5l,374 Patented 0st. 6, 1964 surface of form into which air under pressure is directed. The compressed `air quickly spreads out and is uniformly dispersed from under the patch in all directions to cover the entire upper surface area of each domed molding form and thereby progressively separate and release the form from the set concrete or molded product.

Further objects are to provide aconstruction of maximum simplicity, efficiency, economy and ease of assembly and operation, and such further objects, advantages and capabilities as will later more fully appear and are inherently possessed thereby. Y

In the drawing:

FIGURE l is a perspectiveview Iof a steeldome molding form to which the present invention of ani'olded patch is particularly adapted. i

FIG. 2 is a fragmentary enlarged sectional view taken on the line Z-Zof FlG. 1 and viewed" in the direction of the arrows. i

FIG. 3 is Ia fragmentary enlarged viewn verticalv cross section showing the manner" of separation ofthe form from the concrete or molded product. e

FIG. 4 is an enlarged bottom plan view of the plastic molded patch. l

FIG. I5 is a fragmentary enlarged view in vertical cross section taken o n the line 5 5 of FIG. 3V and showing the manner in which the air pressure enters the plenum chamber 1between the form and the underside of the molded patoL t FIG-6 is a view similar to FIG. 5 but with the patch rotated through an arc of approximately Y `Referring more in detail to the embodiment disclosed in the'drawing, theV steel dome molding form 10 shown is particularly adapted for use in the molding of concrete vtloors, walls and the like of the Waie type. These forms are generally formed of drawn steel contoured to form a dome with an' upper surface 11, sloping sides 12 and a marginal flange 13, with such dome-forms being generally supported `in contiguous relation upon asuitable su'pporting framework in the manner shown in Patent No. 2,850,785. i

ln the disclosed embodiment, lthe upper surface is provided with a central opening 14 in a depending nipple 15, the opening providing an inlet for the 'passage offair underpressure which is directed and `distributed between the molding form 10 andthe molded productY indicated by the reference character 16. While 'this molded product may be composed of any suitable material; in the, illustrative embodiment it consists of apou'red concrete lslurry which has rassumed a set above and betweenthe contiguous forms 10i-n a manner conventional'` in concrete constructions of this general type.

After placement of themolding Yforms preparatory to pouring of the concrete slurry,'the opening or air.- hole 14 is' covered by means of a molded patch or disc 17 formed of a suitable plastic composition capable of 'retaining its shape, and yhaving a diameter`orfsizev s ubstantially greater than that of the `opening 14. This patch has a centrally arranged. depending prong or uted projection 1S on its undersidecapable of being compressed suiciently-to be driven or forced into ,the openingflrt by means of ahammer or other suitable tool. This prongY or projection is shown -in FIGS. 4, 5 and 6` as provided `with axially extending, uniformly spaced flutes or channels 19 'and ribs Ztl' of an external diameter or cross section slightly ylarger than the opening'14 in the upper surface 11 of theV dome `form 10,' whereby the.

plastic compositionof the ribs of the prong are compressed slightly when driven into the opening and securely anchored therein by frictional contact, whereby the patch i7 is retained in contact with and in centered position on the exterior-,surface l1 'of the form 10.

The underside of the disc or' patch 17 is provided with concentrically arranged interrupted ridges 21, 22, 23 and continuous circular ridges or rings 24 and 25 forming annular grooves therebetween. This arrangement of the concentric ridges and rings forms a plenum chamber 26 on the underside of the patch and between it and the upper surface of the dome form 10 permitting an even distribution of the compressed air discharged through the spaced flutes 19 and from there to and around the entire perimeter of the formed plenum chamber. The patch is slightly downwardly curved (FIG. 2) with the outer peripheral edge of the patch downturned as seen in FIG. 5 to normally engage the upper surface 11 of the molding form 1li to define the outer wall of the plenum chamber 26.

After the concrete has set upon the forms with each patch 17 having effectively closed its air opening against the entrance of the concrete slurry, the supporting framework is removed so that the forms may be released from the set concrete by the application of air under pressure.

Release is accomplished bythe operator inserting the reduced tip of a nozzle 27 into the nipple 15 depending from the form as shown in detail in FIGS. 5 and 6, and pressing upwardly on the nozzle and its sealing gasket 28 to establish a tight connection between the nozzle 27, its sealing gasket' 28 and the nipple 15, the sealing gasket 28 being of a resilient material such as natural or compounded synthetic rubber. The nozzle 27 is mounted on the end of a pipe 29 connected to an air hose for conducting air or uid under pressure from a suitable source such as a pump or compressor to the opening 14. IThe air or fluid under substantial pressure enters through the opening 14 and utes 19 into the plenum chamber 26 beneath and formed by the patch 17 and the upper surface of the form 10, and is forced outwardly from the annular grooves formed by the concentric interrupted and continuous ridges 21 to 25, inclusive. These ridges assure a most effective and uniform distribution of the air under pressure around the entire perimeter of the formed plenum chamber and outwardly between the -set concrete and the adjoining or abutting surfaces of the molding form 10.

The iluid emanating from the plenum chamber around the periphery of the patch 17 and seeking passage outwardly Yin progressively enlarging areas, exerts a separating pressure causing gradual and progressive release ofthe vform from the concrete or molded product. This enables the form to be manually withdrawn from the set concrete without the use of tools which might damage therperipheral flanges of the form.

While the patch disclosed in the above patent has had substantial commercial success, the plastic molded patch of the present embodiment is automatically centered and can be applied at less cost and more effectively and positively. Furthermore, the formed plenum chamber of this molded patch operates more eiliciently than that formed by the use of crinkled paper or tape.

While the present novel plastic molded patch has been shown and described as being advantageously applicable for use in the molding of concrete products, it is not my desire or intent to unnecessarily limit the scope or utility ofits improved features by virtue of the illustrative embodiment. It is also contemplated that specific descriptive terms employed herein be given the broadest possible interpretation consistent with the disclosure.V

Having thus disclosed my invention, I claim:

1.'A molded patch for controlling the ow of iluid under pressure through an opening inthe domed wall of a molding form to release and separate the form from vthe molded product by air under pressure, comprising a disc member of Substantially greater diameterY than and covering the opening and having a fluted central projection adapted to be received and anchored in said opening positioning said disc member on the molding form, said disc member having concentric ridges on its undersurface with the inner of the concentric ridges being interruped, said ridges providing with the adjoining surface of said form a plenum chamber communicating with the tintes on said projection, whereby air under pressure supplied to said opening is directed through the iutes into the communicating plenum chamber and from the latter dispersed in all directions to release the form from the molded product.

2. A molded patch as set forth in claim 1, in which said disc member and its iiuted projection are formed of a plastic composition and the ribs defining the flutes of said projection are of a mam'mum diameter somewhat greater than minimum diameter of the opening whereby forcing said projection into the opening frictionally anchors and retains the projection in the opening and retains the disc member centered above the openmg.

3. Means to be aixed to a domed molding form for a concrete oor or wall with the form having an opening for controlling passage therethrough of air under pressure and said means directing the entering air outwardly between the set concrete and the form for releasing and withdrawing the form, said means comprising a molded patch` of substantially greater diameter than and covering the opening and having a downturned peripheral edge and a depending centrally arranged and axially iluted prong adapted to be conformably received and frictionally anchored in the opening, said patch having concentric ridges on its undersurface communicating with the utes on said prong for directing air under pressure through said opening, ilutes and about said ridges and outwardly from the perimeter of the patch to between the adjoining surfaces of the form and set concrete to release the form and permit its withdrawal upon the application of air under pressure to the opening.

4. Means to be aliixed to a domed molding form as set forth in claim 3, in which the undersurface of said patch provides a plenum chamber with the inner of said concentric ridges being interrupted and one or more of the outer ridges being continuous to provide passages communicating with the opening and iiutes of said prong for the outward dispersion of air under pressure. j 5. A plastic patch for a concrete molding form having an opening through its upper surface and a connection to said opening for a source of air under pressure, said patch including a central depending ribbed projection adapted to be frictionally anchored in said opening and provided with axially arranged flutes for the ,passages of air-therethrough, said patch being normally curvedV downward at its periphery to engage said upper surface of the molding form and provided on its undersurface with concentrically arranged ridges including annular interrupted ridges and one or more encompassing circular ridges providing a plenum chamber with the adjoining surface of the form, whereby air under pressure supplied to said connection and opening is discharged through said flutes and directed outwardly therefrom into said plenum chamber and from there betwen the set concrete'and the adjoining surface of the form to separate the form from the set concrete.

2,512,535 Wiltshire et al. June 20, '1950 2,850,785 Y Rushing Sept. 9, 1958 Y -Hick Dec. Il, 1934 

1. A MOLDED PATCH FOR CONTROLLING THE FLOW OF FLUID UNDER PRESSURE THROUGH AN OPENING IN THE DOMED WALL OF A MOLDING FORM TO RELEASE AND SEPARATE THE FORM FROM THE MOLDED PRODUCT BY AIR UNDER PRESSURE, COMPRISING A DISC MEMBER OF SUBSTANTIALLY GREATER DIAMETER THAN AND COVERING THE OPENING AND HAVING A FLUTED CENTRAL PROJECTION ADAPTED TO BE RECEIVED AND ANCHORED IN SAID OPENING POSITIONING SAID DISC MEMBER ON THE MOLDING FORM, SAID DISC MEMBER HAVING CONCENTRIC RIDGES ON ITS UNDERSURFACE WITH THE INNER OF THE CONCENTRIC RIDGES BEING INTERRUPED, SAID RIDGES PROVIDING WITH THE ADJOINING SURFACE OF SAID FORM A PLENUM CHAMBER COMMUNICATING WITH THE FLUTES ON SAID PROJECTION, WHEREBY AIR UNDER PRESSURE SUPPLIED TO SAID OPENING IS DIRECTED THROUGH THE FLUTES INTO THE COMMUNICATING PLENUM CHAMBER AND FROM THE LATTER DISPERSED IN ALL DIRECTIONS TO RELEASE THE FORM FROM THE MOLDED PRODUCT. 